The POST request type does not allow comma-separated identifier lists

[chad-earthscope]

Support comma-separated identifier lists in a POST request. This is a valid selection per the specification:

TA 060A -- BHE,BHN,BHZ 2014-01-01T01:00:00 2014-01-01T03:00:00

but is not currently supported.

This issue is not particularly high priority as the same data is available by reforming the request:

TA 060A -- BHE 2014-01-01T01:00:00 2014-01-01T03:00:00
TA 060A -- BHN 2014-01-01T01:00:00 2014-01-01T03:00:00
TA 060A -- BHZ 2014-01-01T01:00:00 2014-01-01T03:00:00

[chad-earthscope]

Completed. Expansion of lists of identifiers is now common between GET and POST selections.